The present invention relates to continuous availability between sites that are geographically separated from each other, and more specifically, to a multi-site continuous availability computing environment with a recover point objective (RPO) of zero seconds in case of an outage of a site.
In the past, some computer availability and disaster recovery solutions were limited to a maximum distance between sites. Other past solutions required starting systems, applications, and supporting infrastructure on the backup site that could in some cases take several hours to restart. Some past solutions additionally required modifications to software applications, such as database servers, and hardware, such as routers and switches, in order to implement various disaster recovery and continuous availability functions, resulting in relatively high implementation cost. Some past solutions operated at a site level, rather than at a workload level.
These issues have been substantially addressed by continuous availability solutions between sites at unlimited distances. However, it remains very difficult to be able to achieve an RPO of zero seconds when the sites are separated by relatively long distances.